Make VisiblePosition::init to not use being constructed object

Source/core/editing/PositionWithAffinity.cpp

Index: Source/core/editing/PositionWithAffinity.cpp
diff --git a/Source/core/editing/PositionWithAffinity.cpp b/Source/core/editing/PositionWithAffinity.cpp
index fff00e05be23125f5d6518f5a56f0b0edbd40c68..3e902bbeeaf7f34350a84b1a505e98b2d906c579 100644
--- a/Source/core/editing/PositionWithAffinity.cpp
+++ b/Source/core/editing/PositionWithAffinity.cpp
@@ -25,6 +25,12 @@ PositionWithAffinityTemplate<PositionType>::~PositionWithAffinityTemplate()
 {
 }
 
+template <typename PositionType>
+bool PositionWithAffinityTemplate<PositionType>::operator==(const PositionWithAffinityTemplate& other) const
+{
+    return m_affinity == other.m_affinity && m_position == other.m_position;

[tkent, 2015/06/22 06:24:55]

So, an object with m_affinity:UPSTREAM and m_position:null and another object
with m_affinity:DOWNSTREAM and m_position:null are not equal.  Is it an expected
behavior?

[yosin_UTC9, 2015/06/22 06:55:08]

Good catch!
Done.

+}
+
 template class CORE_EXTERN_TEMPLATE_EXPORT PositionWithAffinityTemplate<Position>;
 
 } // namespace blink